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ICF Wall Systems Can Achieve a Tight Thermal Envelope
For many builders, continuous concrete and foam wall systems, such as insulating concrete forms (ICFs), can be an easier and less labor-intensive way to help meet the new, higher energy-efficiency benchmarks consumers are seeking. They may also help qualify homes for energy-efficiency tax incentives.
Properly installed ICFs and similar wall systems can help builders achieve a tight thermal building envelope that can help them achieve an Energy Stae efficiency rating for their homes.
When properly installed, ICFs can provide the insulation and air barriers — with no gaps, voids or compression — needed to complete the U.S. Environmental Protection Agency’s thermal bypass checklist required to earn an Energy Star label.
The added efficiencies can also mean additional points if a home is certified to either the NAHB Model Green Home Building Guidelines or the National Green Building Standard under NAHBGreen.
Air flow through insulation reduces its effectiveness and efficiency. In conventional framing, if batt insulation is not carefully installed tightly around air barriers, framing and finishes, or if it is compressed around electrical wiring, pipes or other obstructions within a wall, the thermal performance of the wall and building envelope can be degraded. A 5% gap in insulation coverage can reduce the effective R-value by as much as 50%.
Potential trouble spots for completing the thermal bypass checklist in conventional construction are shown in the accompanying traditional wall section illustration.
A properly installed two-story ICF exterior wall section assembly, as shown in the accompanying ICF wall section illustration, has fewer areas requiring special consideration and inspection than traditional construction. Building with ICFs, removable forms, precast concrete or similar concrete and foam systems can eliminate critical coordination issues and construction details that would have to be addressed and verified when building typical Energy Star-compliant exterior walls.
As with conventional construction, care is needed to properly install ICFs and other concrete wall systems in order to achieve energy-efficiency goals.
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ICF Wall System
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Traditional Wall Section
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ICF Construction Courses
To help builders and contractors learn how to install ICFs, the Concrete Home Building Council is offering two educational courses through the Home Builders Institute (HBI).
“Building with Insulating Concrete Forms” is an eight-hour course that provides the traditional home builder with the information needed to evaluate and start using ICFs.
“Insulating Concrete Forms Installation” is a one- or two-day course that provides attendees with the information and basic skills needed to correctly install ICFs.
For more information, visit the HBI Web site at www.hbi.org, the Concrete Home Building Council Web site at www.nahb.org/concrete or the Portland Cement Association at www.cement.org.
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